Block search
Block search is a method to structure your search. You need to use a search tool that understands boolean operators and preferably allows you to use different lines for searching (i.e. a bibliographic database).
Step 1. Identify the different concepts that you would like your search results to include.
Examples:
Research question |
Concepts |
Does climate change effect bird migration? |
"climate change", bird, migration |
Is mycorrhiza effected by clearcutting in boreal forests? |
clearcutting, "boreal forest", mycorrhiza |
How does bacteria interact with myeloid cells to manipulate their function?
|
bacteria, "myeloid cells", manipulation |
Is aquatic biodiversity affected by climate change? |
aquatic, biodiversity, "climate change" |
Step 2. Put the different concepts on different lines (=blocks) with AND in between.
If you can't see the different lines you may have to go to "advanced search". Example:
Block 1 |
aquatic |
|
AND |
Block 2 |
biodiversity |
|
AND |
Block 3 |
"climate change" |
In the search tool, it may look something like this:

Step 3. Add synonyms, alternative expressions, spelling variants etc. on each line/block with OR.
Don't forget truncation and phrase search! Example:
Block 1 |
aquatic OR lake OR limn* OR marine OR ocean OR freshwater OR river |
|
AND |
Block 2 |
biodiversity OR diversity OR "genetic variation" OR "species richness" |
|
AND |
Block 3 |
"climate change" OR "global change" OR "global warming" OR "greenhouse effect" |
Structuring your search like this is a way of telling the search tool that you want all results to include at least one thing from block 1, at least one thing from block 2 and at least one thing from block 3.
General tips
An alternative to using lines is to put each "line" within parentheses. However, when doing advanced searches it is easy to put a single parenthesis wrong which will mess up your whole search. We suggest you stick with the lines if you can (however not all search tools have the option of lines). Example:
(cat OR feline) AND (behavior OR behaviour OR etology)
If you get strange results it is likely that you have forgotten a boolean operator. For example, if you search for
(cat OR feline) AND (behavior OR behaviour etology) forgot an "OR" between behaviour and etology
What you are really searching for is:
(cat OR feline) AND (behavior OR behaviour AND etology), which means that etology must be in all results, reducing the result list dramatically.